1. Field of the Invention
The present invention relates to an information recording and reproducing apparatus which can prevent the dishonest use or forgery of various variable cards such as cssh cards, credit cards, etc.
2. Description of the Prior Art
At present, various cards are widely used in the form of cash cards for bank transactions, credit cards for merchandise dealing, etc. A magnetic card among the above-mentioned cards is usually formed with a magnetic striped recording area with a constant width on either side of the magnetic card, in order to record specific information of the card owner in the form of magnetic data.
Prior-art methods of recording data magnetically on the magnetic card will be described with reference to FIGS. 1 (a) and (b). In FIG. 1 (a), the magnetic striped data recording area 30 is divided into a number of data recording areas 31 and data are recorded along a plurality of tracks 32 in the longitudinal direction of the magnetic striped data recording area 30. Here, a magnetic head is arranged relative to the magnetic stripe in such a way that the longitudinal direction of a magnetic gap of the magnetic head is perpendicular to the recording tracks 32.
Here, if an angle subtended by the longitudinal direction of the magnetic head gap and the lateral direction of the magnetic striped recording area 30 is defined as a magnetization angle .theta., the magnetization angle of the magnetic stripe 30 shown in FIG. 1 (a) is 0 degrees and that shown in FIG. 1 (b) is +.theta..
In the prior-art method of recording and reproducing data on or from a magnetic card, since the magnetization angle is uniformly fixed as 0 (in the case of the stripe shown in FIG. 1 (a)) or +.theta. degrees (in the case of the stripe shown in FIG. 1 (b)), the following problems arise: where the magnetic card is applied to a cash card for bank transactions, for instance, in case this card falls into another's hand due to loss or burglary, an identification number recorded on the magnetic card can easily be discriminated through a magnetic card reader. This is because in the prior-art apparatus, since the data recording or reproducing direction (the magnetization direction) of the magnetic head is always kept at a constant angle relative to the movement direction of the recording medium (card), data written on the recording medium can easily be read by gradually changing the angle of the magnetic head relative to the recording medium. As a result, the magnetic card is used dishonestly through a cash dispener. In addition, in the case of the prior-art magnetic recording method of magnetic cards, it is relatively easy to copy other people's information onto another magnetic card by means of a magnetic card reader. In any case, there exists a problem such that cards may be used dishonestly and therefore there exists a need of preventing dishonest use or forgery of cards, because a great quantity of magnetic cards have come into wide use at present.